<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>

	<script type="text/javascript">
		
		let str1="喜羊羊"
		let str2="懒羊羊"
		let temp
		temp=str1
		str1=str2
		str2=temp
	</script>

</body>
</html>